Modeling pre-evacuation delay by evacuees in World Trade Center Towers 1 and 2 on September 11, 2001: A revisit using regression analysis $ M.F. Sherman a , M. Peyrot b , L.A. Magda c , R.R.M. Gershon c,n a Loyola University Maryland, Department of Psychology, 4501 N. Charles St., Baltimore, MD 21210, USA b Loyola University Maryland, Department of Sociology, 4501 N. Charles St., Baltimore, MD 21210, USA c Columbia University, Mailman School of Public Health, Department of SocioMedical Sciences, 722W. 168th St., Room 939, New York, NY 10032, USA article info Article history: Received 27 September 2010 Received in revised form 30 June 2011 Accepted 1 July 2011 Available online 20 July 2011 Keywords: Evacuation World Trade Center Decision making Predictors of pre-evacuation delay abstract We have tested a linear regression model to identify significant predictors of pre-evacuation delay in a sample of evacuees enrolled in the World Trade Center Evacuation Study. We have found that pre-evacuation delay was greater when there were more environmental cues, more seeking out of information, and more pre-evacuation actions. Additionally, higher perceived risk was predictive of shorter pre-evacuation delay times. These findings are compared and contrasted with an analysis of participants in the National Institute of Standards and Technology investigation of the World Trade Center disaster, recently reported by Kuligowski and Mileti (2009). Both studies reported factors associated with pre-evacuation delay that were similar to those associated with community evacua- tion. Additionally, we found that greater knowledge and greater emergency preparedness were associated with greater perception of risk. Greater emergency preparedness was negatively related to pre-evacuation delay within World Trade Center Tower I, but within World Trade Center Tower II, the relation between emergency preparedness and pre-evacuation delay was positive. These findings have implications for training of occupants of high-rise buildings. & 2011 Elsevier Ltd. All rights reserved. 1. Introduction The efficacy of decision making in large-scale natural or man-made disasters, which require evacuation from high-rise buildings, can determine whether someone survives or perishes. Understanding the processes that are involved in decision mak- ing may help to improve evacuation education, training, and procedures for successful escape from high-rises. To this end, researchers affiliated with the National Institute of Standards and Technology (NIST, [1]), tested a path analytic model of pre-evacuation delay based upon theories addressing community disasters and building-fire evacuations. For their analysis, they used survey data collected through telephone interviews between December 3, 2003 and January 23, 2004 from 803 individuals who evacuated from either World Trade Center (WTC) Tower 1 or 2 on September 11, 2001. Their findings clearly established support for their model and delineated the important factors that appeared to be predictive of pre-evacuation delay. Researchers from the Mailman School of Public Health at Columbia University conducted a similar survey of the WTC Towers evacuees between May 28, 2004 and August 8, 2005 as part of the WTC Evacuation Study (WTCES). In order to extend the generalizability of the findings of Kuligowski and Mileti [1], we recently tested their model using linear regression analysis of data from an independent sample of WTCES evacuees and with different operational definitions of key variables. Prior community disaster and building-fire evacuation research reveals that people hesitate to leave their current situation, even when there are verbal and environmental cues suggesting that they should evacuate [2–4]. Factors that poten- tially contribute to pre-evacuation delay include: (1) environmen- tal cues [1,2,5–13]; (2) proximity to safety [1,11,13–24]; (3) amount of incoming information [1,13,25–31]; (4) the seeking of additional information [1–3,9,13,32–35]; (5) perceived risk [1,3,13,36–42]; and (6) number of activities performed prior to beginning evacuation [1,2,9,10,13,35,43–45]. For the WTC crisis situation, peri-event environmental cues included such things as: seeing the airplane approaching and/or striking the towers, physically feeling the impact of the planes, smelling something unusual, experiencing heat, or seeing smoke, flames, and flying debris. Proximity to safety refers to the distance a person is from relative safety, or in this instance, street level. The amount of incoming information refers to passively receiving or obtaining Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/firesaf Fire Safety Journal 0379-7112/$ - see front matter & 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.firesaf.2011.07.001 $ Funding: This project was supported under a cooperative agreement from the Centers of Disease Control and Prevention (CDC) through the Association of Schools of Public Health (ASPH). Grant no. (S2133-22/22) U36/CCU300430-22. The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of CDC or ASPH. n Corresponding author. E-mail address: rg405@columbia.edu (R.R.M. Gershon). Fire Safety Journal 46 (2011) 414–424